Re: SPI Maximum speed
Posted: Thu Oct 11, 2018 2:43 am
Note the crystal doesn't really matter; the ESP32 normally uses a PLL to derive the CPU frequency from this, then divides the CPU frequency by an applicable number to get the 80MHz APB clk.
ESP32 Official Forum
anakyr wrote:I'm 100% sure that I have a 40MHz crystal. Check attachment too. I will try first to include SPI_DEVICE_NO_DUMMY in order to ignore this checking, as the error message in red is saying. If it doesn't work, I will go to the registers